Add IPFS repo stats to brave://ipfs page

[bbondy]

Add IPFS repo stats to brave://ipfs page, something like:

NumObjects: 838
RepoSize:   32340835
StorageMax: 1000000000
RepoPath:   /Users/bbondy/Library/Application Support/BraveSoftware/Brave-Browser-Nightly/brave_ipfs
Version:    fs-repo@10

You can run this manually to get the data:
./go-ipfs_v0.7.0_darwin-amd64 --api=/ip4/127.0.0.1/tcp/45004 repo stat
But see below for how to get it through the API port like we do for getting the address config that we display on that same page.

That way when you clear cache for example, you can see it got lower.

[yrliou]

HTTP API reference: https://docs.ipfs.io/reference/http/api/#api-v0-repo-stat, we could use IpfsService::CreateURLLoader to use HTTP API to retrieve the result.
See IpfsService::GetAddressesConfig & IpfsService::OnGetAddressesConfig for reference.

[stephendonner]

Verified FIXED using inline testcase on

Brave	1.21.51 Chromium: 88.0.4324.152 (Official Build) beta (x86_64)
Revision	6579930fc53b4dc589c042bec9d0a3778326974d-refs/branch-heads/4324@{#2106}
OS	macOS Version 11.2.1 (Build 20D74)

Checked and verified that reloading the tab updates:

• connected peers
• objects
• size

---

Verification passed on

Brave	1.21.52 Chromium: 88.0.4324.152 (Official Build) dev (64-bit)
Revision	6579930fc53b4dc589c042bec9d0a3778326974d-refs/branch-heads/4324@{#2106}
OS	Ubuntu 18.04 LTS

Verified the above test plan
Verified that both connected peers, objects and size were present, with sane values

---

Verification passed on

Brave | 1.21.56 Chromium: 88.0.4324.152 (Official Build) dev (64-bit)
-- | --
Revision | 6579930fc53b4dc589c042bec9d0a3778326974d-refs/branch-heads/4324@{#2106}
OS | Windows 10 OS Version 2004 (Build 19041.804)

Checked and verified that reloading the tab updates:

• connected peers
• objects
• size